Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opport...Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opportunities for exploring novel topological phenomena and fascinating applications.Utilizing a low-temperature scanning tunneling microscope,we construct breathing-kagome lattices with Fe adatoms on Ag(111)and investigate their electronic properties.We observe the higher-order topological boundary states in the topological phase but not in the trivial one,which is consistent with the theory.These states are found to be robust against the removal of bulk or edge adatoms.Further,we show the arbitrary positioning of these states either at corner,edge,or bulk sites by slightly modifying their neighbors.Our study not only demonstrates the formation and robustness of the electronic higher-order topological boundary states in real atomic systems but also provides a route for controlling their positions.展开更多
Covalent organic frameworks(COFs)are emerging porous polymer materials.They are characterized by functionalization of their surface chemical properties,and excellent physical and chemical stability.This review focuses...Covalent organic frameworks(COFs)are emerging porous polymer materials.They are characterized by functionalization of their surface chemical properties,and excellent physical and chemical stability.This review focuses on the advances of COFs in lithium ion batteries(LIBs)regarding the active sites and dis cusses the redox mechanisms of active sites.Furthermore,the modification methods of COFs as elec trode materials are analyzed and summarized.展开更多
基金supported by the National Key R&D Program of China(Grant Nos.2024YFA140850,2022YFA1403601,and 2023YFC2410501)the National Natural Science Foundation of China(Grants Nos.12241402,12474059,12274203,12374113,and 12274204)。
文摘Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opportunities for exploring novel topological phenomena and fascinating applications.Utilizing a low-temperature scanning tunneling microscope,we construct breathing-kagome lattices with Fe adatoms on Ag(111)and investigate their electronic properties.We observe the higher-order topological boundary states in the topological phase but not in the trivial one,which is consistent with the theory.These states are found to be robust against the removal of bulk or edge adatoms.Further,we show the arbitrary positioning of these states either at corner,edge,or bulk sites by slightly modifying their neighbors.Our study not only demonstrates the formation and robustness of the electronic higher-order topological boundary states in real atomic systems but also provides a route for controlling their positions.
基金support of the National Natural Science Foundation of China(No.21875206,21403187)the Natural Science Foundation of Hebei Province(No.B2019203487).
文摘Covalent organic frameworks(COFs)are emerging porous polymer materials.They are characterized by functionalization of their surface chemical properties,and excellent physical and chemical stability.This review focuses on the advances of COFs in lithium ion batteries(LIBs)regarding the active sites and dis cusses the redox mechanisms of active sites.Furthermore,the modification methods of COFs as elec trode materials are analyzed and summarized.
